POS0132 OUTCOMES FOLLOWING SWITCHING FROM ORIGINATOR TO BIOSIMILAR IN CHILDREN AND YOUNG PEOPLE WITH JIA
Authors: L. Kearsley-Fleet, E. Baildam, M. Beresford, S. Douglas, H. Foster, T. Southwood, K. Hyrich
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> There are many biosimilar products available to use in children and young people with JIA. Due to competitive pricing, patients are being switched from biologic originator to biosimilar (non-medical switch). <h3>Objectives</h3> This analysis aims to describe characteristics of, and outcomes, following TNF-inhibitor originator to biosimilar switch in JIA. <h3>Methods</h3> All patients in the UK JIA Biologics Register switching from an originator to a biosimilar of the same product were identified. Patient characteristics are presented, including time on originator prior to switch. Patients were followed until their final follow-up form was returned. For those with &gt;1 year of follow-up post-switch, treatment persistence and reasons for stopping are described. <h3>Results</h3> As of 24-Nov-2022, 211 children and young people had switched from originator to biosimilar; 132 adalimumab, 55 etanercept, and 24 infliximab (table 1). Switching was seen in all ILAR categories. Patients were predominantly female (64%), median age at JIA diagnosis six years, 11 years at originator start, 14 years at biosimilar start, median time on originator 2.2 years. Most patients had started originator as their first biologic (73%) and most started biosimilar with no significant treatment gaps. Six patients reported &gt;1 year gap between originator stop and biosimilar start, suggesting a planned period off biologic therapy (two stopped for adverse event, four unknown). Of the 143 patients with &gt;1 year of follow-up available after switching (median 1.9 years per patient), 82 remained on biosimilar at their final follow-up, whilst 61 had stopped therapy. Of those who stopped, 11 had stopped for remission, 13 stopped for ineffectiveness, 20 for adverse event, and 17 other/missing reason. Forty-one patients then re-started biologic therapy (including four of the remission patients); 17 switched back to the originator mostly due to an adverse event on the biosimilar, and 24 started a different biologic therapy mostly due to inefficacy of the biosimilar. <h3>Conclusion</h3> Many children with JIA have now been switched from TNF-inhibitor originator to biosimilar product, with the majority still receiving their biosimilar after one year. Switching back to originator was uncommon, 12% overall after one year, suggesting good tolerance of non-medical switching in this patient population. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Lianne Kearsley-Fleet: None declared, Eileen Baildam: None declared, Michael Beresford: None declared, Sharon Douglas: None declared, Helen Foster: None declared, Taunton Southwood: None declared, Kimme Hyrich Speakers bureau: Non-personal speaker's fees from Abbvie, all unrelated to this abstract., Grant/research support from: Grant income from BMS, UCB, and Pfizer, all unrelated to this abstract, and is supported by the NIHR Manchester Biomedical Research Centre.